zulip/web/tests/example6.test.js

70 lines
2.3 KiB
JavaScript

"use strict";
const assert = require("node:assert/strict");
const {make_stub} = require("./lib/stub");
const {run_test, noop} = require("./lib/test");
/*
The previous example was a bit extreme. Generally we just
use the make_stub helper that comes with zjsunit.
We will step away from the actual Zulip codebase for a
second and just explore a contrived example.
*/
run_test("explore make_stub", ({override}) => {
// Let's say you have to test the following code.
const app = {
/* istanbul ignore next */
notify_server_of_deposit(deposit_amount) {
// simulate difficulty
throw new Error(`We cannot report this value without wifi: ${deposit_amount}`);
},
/* istanbul ignore next */
pop_up_fancy_confirmation_screen(deposit_amount, label) {
// simulate difficulty
throw new Error(`We cannot make a ${label} dialog for amount ${deposit_amount}`);
},
};
let balance = 40;
function deposit_paycheck(paycheck_amount) {
balance += paycheck_amount;
app.notify_server_of_deposit(paycheck_amount);
app.pop_up_fancy_confirmation_screen(paycheck_amount, "paycheck");
}
// Our deposit_paycheck should be easy to unit test for its
// core functionality (updating your balance), but the side
// effects get in the way. We have to override them to do
// the simple test here.
override(app, "notify_server_of_deposit", noop);
override(app, "pop_up_fancy_confirmation_screen", noop);
deposit_paycheck(10);
assert.equal(balance, 50);
// But we can do a little better here. Even though
// the two side-effect functions are awkward here, we can
// at least make sure they are invoked correctly. Let's
// use stubs.
const notify_stub = make_stub();
const pop_up_stub = make_stub();
// This time we'll just use our override helper to connect the
// stubs.
override(app, "notify_server_of_deposit", notify_stub.f);
override(app, "pop_up_fancy_confirmation_screen", pop_up_stub.f);
deposit_paycheck(25);
assert.equal(balance, 75);
assert.deepEqual(notify_stub.get_args("amount"), {amount: 25});
assert.deepEqual(pop_up_stub.get_args("amount", "label"), {amount: 25, label: "paycheck"});
});